Most surgical neurological procedures require accurate placement of medical instruments within the patient's brain. A common neurological surgical procedure is a ventriculostomy in which a cerebral ventricle drain, shunt or catheter is implanted. The purpose of the drain or shunt (with or without a transducer or fiberoptic device) is to relieve high pressure cerebrospinal fluid (CSF) in a patient's cerebral ventricles resulting from congenital brain malformations, acute or chronic infections, tumors, intraventricular hemorrhage, normal pressure hydrocephalus or other intracranial space-occupying lesions, as well as to provide a reliable means to measure intracranial pressure or to deliver medication into the cerebrospinal fluid space.
Procedures for the placement of ventricular drains, shunts and catheters rely on the skill of the neurosurgeon. These procedures are often expensive and time consuming. After imaging the brain, the neurosurgeon forms a burr hole in the skull and guides a catheter through the burr hole toward landmarks on the ipsilateral or contralateral of the patient's head. The neurosurgeon must accurately conceptualize the internal topography of the brain during the procedure, and rely on this conceptualization to effectively place the catheter within the cerebral ventricle. In some procedures, the neurosurgeon checks the location of the catheter by imaging another CT scan of the brain following the operation. By verifying the position of the catheter within the brain, the neurosurgeon can effect longer shunt patency and decrease morbidity rates due to shunt malpositioning, as well as assure the accurate delivery of medication within the ventricle and the accurate measurement of intracranial pressure.